1. For the following examples say if it would be most appropriate to use a z-test, one sample t-test, independent sample t-test, paired (dependent) samples t-test, or one way ANOVA.

a. You want to analyze data from a study comparing two groups that was manipulated between subjects.

b. You find out the researchers from the study described in letter a actually had three groups instead of 2 and the researchers want to compare all 3 groups.

c. Your stats professor wants you to compare a sample mean to a population mean, but the population mean is unknown.

d. You want to compare pre-test and post-test scores for a group of students who watched a video about z-tests

e. You want to compare a sample mean to a population mean and thankfully you know the population mean.

2. A researcher with Verizon wants to know if customer satisfaction ratings are the same before and after talking to a customer service representative. The data for a within subjects study with a sample of 6 participants is presented below:

Participant

Pre-Rating/Post-Rating

A/ 22

B/ 34

C/ 35

D/ 45

E/ 23

F/ 32

a. State your null and research hypotheses in both words and symbols.

b. Use a two-tailed hypothesis test with an alpha level of 0.05 to determine whether there was a difference in satisfaction ratings before and after talking with a customer service representative.

c. What degrees of freedom should be used to determine the critical t-value?

d. What is the critical t-value to make a decision about the null hypothesis?

e. What is the decision about the null hypothesis?

f. Calculate and interpret the effect size

3. You collect some data where three separate groups of participants ate either plain, blueberry, or chocolate chip pancakes and were asked to rate how good their pancakes were on a scale from 1-10. Their ratings and sums of ratings for each group are listed below.